Starter control including means to prevent starter energization while engine is running



E.KEUCHEN ARTER CONTROL INCLUDING MEANS TO PREVENT STARTER ENERGIZATION WHILE ENGINE IS RUNNING Aug. 2, 1966 ST Filed June 26, 1964 INVENTOR.

ER/CH KEUCHEN United States Patent 3,264,484 STARTER CQNTRUL INCLUDING MEANS TO PREVENT STARTER ENERGIZATION WHELE ENGINE IS RUNNING Erich Keuchen, Aachen, Germany, assignor to Garbo, Lahmeyer & Co. AG, Aachen, Germany, a corporation of Germany Filed dune 26, 1964, Ser. No. 378,403 Claims priority, application Germany, June 28, 1%3, G 38,058 3 Claims. Cl. 290-138) This invention relates to a starter control and, more particularly, to electrical circuitry for regulating the starter motor of an internal combustion engine.

In attempting to prolong the life of starter motors and the associated mechanisms and to prevent breakage, a number of problems have presented themselves. The destruction of starter parts can be eliminated to a considerable extent by preventing the unintentional energization of the starter motor while the engine is running. In addition, the life of the starter can be extended by limiting the operation of the starter to the beginning of the engine operation, so that the operation of the starter during the later high speed rotation of the engine is avoided. A large number of devices are known which eliminate the energization of the starter while the engine is running. Most of them have the disadvantage that they do not offer complete security against premature repeated starting after an interrupted starting, since they are responsive to only one characteristic of the engine. Those other devices which are responsive to several characteristics of the engine cannot be easily mounted because of mechanical connections and, furthermore, they do not solve the problem completely.

Another proposal has been that the starter be provided with a relay which is used to control the starting; then, the generator and the coils are connected to an oil pressure switch. This arrangement provided a delaying action for the repetition of the starting procedure which, in many cases, was too long, because of the slow rate of reduction of the oil pressure. There is also a device, including a timer, by which the turning-on of the starter is prevented until a certain period has passed after the engine stops. For this arrangement, it is necessary to have a sensitive electrolytic condenser; this takes up considerable space with the three relays which are assigned to it and still doesnt accomplish all the desired functions. Such an arrangement can even be dangerous when the starter switch is not working properly and can switch on the starter. These and other difliculties experienced with the prior art devices have been obviated in a novel manner by the present invention.

It is, therefore, an outstanding object of the invention to provide a starter control which will prevent undue wear and destruction of the starter.

Another object of this invention is the provision of a starter control which not only prevents the operation of the starter while the engine is running but also stops the operation of the starter when the engine starts and begins to speed up.

A further object of the present invention is the provision of a starter control which assures that the starter will not be subjected to the high-speed operation of the engine after starting.

It is another object of the instant invention to provide a starter control which is simple in construction, inexpensive to manufacture, and which is capable of a long life of useful service with a minimum of maintenancc.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

The character of the invention, however, may be best understood by reference to one of its structural forms, as illustrated by the accompanying drawing in which:

The single figure is an electrical schematic diagram of a starter control embodying the principles of the present invention.

In general, the invention involves removing the disadvantages of the previously known arrangements for starting an engine, the invention operating by means of a switching relay located ahead of the starter motor and controlling the starter operation by closing a contactor; the switching relay isiprovided with a pull coil and a holding coil which can be energized when the starter switch is closed. The holdin coil is connected in series with the generator and is of such a size that it will release the relay when the generator voltage exceeds a predetermined value and will open the contactor. In the circuit of the pull coil is connected a rest contactor forming part of a check relay having several coils. A pull coil of the check relay is in parallel with the starter switch and another coil carrying the same voltage as the generator and operates with the small voltage induced.

by the generator. The check relay also has a holding coil which is energized directly from the battery without the intervention of the starter switch.

Referring to the drawing, the starter control, indicated generally by the reference numeral 10, is provided with an automotive battery 11 which is connected on one side to ground and on the other side to a switchboard 12. A manual starter switch 13 is connected on one side to the switchboard and on the other side through a starter protection circuit 14 to the operating relay of a starter motor 15, the other side of which is connected to ground. A generator 16 is driven by an internal combustion engine (not shown) which is to be started and is connected on one .side to the protection circuit 14 and on the other side to ground.

In the operation of the vehicle containing the engine to be started, the apparatus is placed in readiness by the closure of all switches in the switchboard 12. Whenthe starter switch 13 is closed, current will pass through a pull coil 17 of a switch relay 18, forming part of the circuit 14. The relay plunger is moved to close a nor mally-open contactor 19 which permits current to pass to the operating relay of the starter motor 15 and energize 50 1t When the contactor 19 is closed, current also passes through a rectifier 20 and through a pull coil 21 associated with a check relay, 22. The energizatfon of this coil of the relay opens a normally-closed contactor 23, which contactor is connected in series with the pull coil 17 of the switch relay 18 and, when opened, deenergizes this coil. Connected in parallel with the pull coil 17 and forming part of the relay 18 is a holding coil 24 which is also energized when the starter switch 13 is closed. Therefore, even though the coil 17 is deenergized (by the opening of the contactor 23), the relay remains activated and the contactor 19 remains closed.

The holding coil can, of course, be released at any time by opening the starter switch 13 especially after the engine has started. When the generator 16 is up to full' rotation, a voltage appears at its terminals and this volt-.

Patented-August 2, 1966 erator 16 produces a higher voltage. When the generator voltage equals that of the battery, the holding coil 14 will cease to be energized and the switch relay 18 drops out. The contactor 19 opens and current does not flow to the starter motor. The starter mechanism is entirely disconnected from the engine in the usual way. This procedure prevents rapid wear of the starter mechanism which would otherwise exist due to high-speed rotation and consequent damage due to centrifugal force.

A point 25 between the switchboard 12 and the starter switch 13 is connected to a holding coil 26 forming part of the check relay 22. This coil is energized directly from the switchboard without closure of the starter switch 13, but is not large enough to open the contactor 23 by itself. However, when the contactor 19 is closed, the pull coil 21 energized, and the relay 22 is operated, the contactor 23 is opened. The relay can be maintained in this condition by the holding coil 26 alone, even when the switch relay 18 is de-energized and the contactor 19 is opened. In addition, the relay 22 is further energized by means of a third coil 27 which is connected on one side to the generator high voltage terminal and on the other side to ground. This coil is so designed that it is possible by a very low generator voltage, say, 0.5 volt, to hold the relay in or, if it drops out, to pull it in again. Therefore, it can be seen that the check relay 12, after having been energized by the closing of the starter switch 13, is held in energized condition until the generator 16 no longer is rotating and the switchboard 12 is switched off.

As long as the check relay 22 is energized, another start-up procedure cannot be carried out. The contactor 23 is in open condition and interrupts the circuit of the pull coil 17 of the switching relay 18. This blocking begins with the first reaction of the starting procedure, because the pull coil 21 of the check relay 22 is energized (since it is connected in parallel with the contactor 19 of the relay 18) and it interrupts the circuit of the pull coil 17 by opening the normally-closed contactor 23. In addition, the open-switch status of the check relay 22 will be maintained by the holding coil 26, which is switched on by the switchboard 12, and also by the energization of the third coil 27 by the generator.

In order to attempt another starting cycle, it is necessary to switch otf the switchboard 12, and the engine must be stopped. When the engine speed has dropped below a certain value and the generator voltage has dropped with it to a value determined by the size of the coil 27, the check relay 22 drops out and a new starting cycle is possible. The switchboard 12 must be switched on and the starter switch 13 closed. The larger Diesel engines come to a complete stop within the elapsed time, so that there is no danger of damage to the starter pinion or the engine flywheel rim.

The apparatus described above satisfies all of the functions necessary to protect the starter. The starter is not only switched oh by higher engine revolution after the start of the engine, but is also blocked against a re-starting operation right from the beginning of the engine action to the complete stand-still of the engine. By a suitable arrangement of the operative parts, it is possible to assure that, in addition to the stopping of the engine, very little time has to pass before the starter can be switched on again. Especially is it assured that the starter will be prevented from operating while the engine is still running, as can easily happen in the case of quietly-running large automotive engines, or as may well happen on large buses with engines in the rear or mounted underneath. The arrangement described may be used on Diesel-Otto and 2-cycle engines. For example, many of the previously-known constructions are not usable with a starter motor used in connection with 2-cycle engines, because they do not have an oil switch and they could not be used in connection with Diesel engines, because they have no ignition switch.

For operation with Otto or with 2-cycle engines in which the ignition and starter switch are combined, it is recommended that under certain circumstances the holding coil 26 of the check relay 22 be omitted or, at least, not connected. Naturally, this results in a repeated blocking, as is experienced with ignition switches operated mechanically, but, in any case, it indicates that on smaller engines an additional security is necessary because the coil of the check relay (which is energized by the generator 27) is a sensitive indicator of the rotation of the engine and the generator.

The present apparatus for controlling the starter is recommended even in those cases in which the internal combustion engine does not have its own generator. In such a case, the terminal of the starter protection switch 14 which would normally be connected to the generator must be connected direct to ground. Most of the functions are retained in this arrangement even when the forced switch-off of the starter after the engine start-up has to be omitted. The behavior of the present apparatus is very interesting in the case where the generator (because of a short circuit or because of sticking brushes) does not operate. When in this case the terminal of the starter protection circuit 14 is not even connected to ground, there is still a second circuit over the field coil 29 associated with the rotor 28 of the generator. Thiscoil operates through the voltage regulator (not shown), so that no complications need be feared because of non-operation of the generator.

Dangerous self-starting, which can happen occasionally because of the lack of operation of the starter protection circuit due to sticking contacts of the contactor 19, cannot occur with the present invention. The blocking is still intact with the starter protection circuit in accordance with the invention until the switchboard 12 is shut off. Also, an unintentional starting cycle cannot occur because of bridging of the starter switch 13 during switchoil of the engine.

Double security against unintentional drop-out of the check relay 22 is provided so that it can be energized by means of pull coil 21 and also over the third coil 27, and the release of the energized check relay can be accomplished alternatively by means of the coils 26 and 27.

Since the starter protection circuit 14 is connected only electrically to the starter motor, etc., the mounting is very simple and, since only two relays are used, the material cost is quite low. Its small dimensions make it easy to locate in a suitable place. As has been explained already, the starter control can be applied to Diesel-Otto and 2- cycle engines. In addition, it is possible, if necessary, to separate the switching and controlling circuits of the switch relay 18 and to connect the contactor 19 directly with the switchboard 12 and the battery 11, so that the starter circuits are free of the heavy currents and are uncritical with respect to length and cross-section.

It is obvious that minor changes may be made in the form and construction of the invention without departing from the material spirit thereof. It is not, however, desired to confine the invention to the exact form herein shown and described, but it is desired to include all such as properly come within the scope claimed.

The invention having been thus described, what is claimed as new and desired to secure by Letters Patent is:

1. A starter control for use with the starter motor, starter switch, battery, and generator of an internal combustion engine, comprising (a) a switch relay having a normally-open contactor,

(b) a pull coil forming part of the switch relay,

(c) a holding coil forming part of the switch relay,

(d) a check relay having a normally-closed contactor,

(e) a pull coil forming part of the check relay,

(f) a holding coil forming part of the check relay,

(g) a third coil forming part of the check relay, the

pull coil of the switch relay and the normally-closed contactor being connected in series from a first point between the starter switch and the normally-open contactor on the one hand to ground on the other hand, the pull coil of the check relay being connected in series with a rectifier on the one hand from a second point between the normally-open contactor and the starter motor on the one hand and ground on the other hand, the holding coil of the switch relay being connected from the said first point to the generator and the third coil of the check relay being connected from ground to the generator, the holding coil of the check relay being connected from a third point between the battery and the starter switch on the one hand and ground on the other hand.

2. A starter control as recited in claim 1, wherein a tor of the switch relay to the starter motor, the holding coil of the switch relay being connected on one side to the starter switch and on the other side to the generator, the pull coil of the switch relay being connected 011 one side to the starter switch and on the other side to the contactor of the check relay, one side of the contactor of the switch relay being connected through a rectifier to one side of the pull coil of the check relay, the other side of which is connected to ground, one side of the holding coil of the check relay being connected to ground and the other side being connected to a point between the starter switch and the battery, 21 switchboard being mounted between the said point and the battery, and the third coil of the check relay being connected switchboard is connected between the said third point and the battery.

3. A starter control for an internal combustion engine, comprising (a) a battery, (b) a starter switch connected to the battery, (c) a starter motor, (d) a generator driven by the motor, and (e) a starter protection circuit connected between the switch, the motor, and the generator, the said circuit having a switch relay with a pull coil, a holding coil, and a normally-open contactor and having a check relay with a pull coil, a holding coil, a third coil, and a normally-closed contactor, the starter switch being connected through the normally-open contacfrom ground to the generator.

References Cited by the Examiner UNITED STATES PATENTS ORIS L. RADER, Primary Examiner.

G. SIMMONS, Assistant Examiner. 

1. A STARTER CONTROL FOR USE WITH THE STARTER MOTOR, STARTER SWITCH, BATTERY, AND GENERATOR OF AN INTERNAL COMBUSTION ENGINE, COMPRISING (A) A SWITCH RELAY HAVING A NORMALLY-OPEN CONTACTOR, (B) A PULL COIL FORMING PART OF THE SWITCH RELAY, (C) A HOLDING COIL FORMING PART OF THE SWITCH RELAY, (D) A CHECK RELAY HAVING A NORMALLY-CLOSED CONTACTOR, (E) A PULL COIL FORMING PART OF THE CHECK RELAY, (F) A HOLDING COIL FORMING PART OF THE CHECK RELAY, THE (G) A THIRD COIL FORMING PART OF THE CHECK RELAY, THE PULL COIL OF THE SWITCH RELAY AND THE NORMALLY-CLOSED CONTACTOR BEING CONNECTED IN SERIES FROM A FIRST POINT BETWEEN THE STARTER SWITCH AND THE NORMALLY-OPEN CONTACTOR ON THE ONE HAND TO GROUND ON THE OTHER HAND, THE PULL COIL OF THE CHECK RELAY BEING CONNECTED IN SERIES WITH A RECTIFIER ON THE ONE HAND FROM A SECOND POINT BETWEEN THE NORMALLY-OPEN CONTACTOR AND THE STARTER MOTOR ON THE ONE HAND AND GROUND ON THE OTHER HAND, THE HOLDING COIL OF THE SWITCH RELAY BEING CONNECTED FROM THE SAID FIRST POINT TO THE GENERATOR AND THE THIRD COIL OF THE CHECK RELAY BEING CONNECTED FROM GROUND TO THE GENERATOR, THE HOLDING COIL OF THE CHECK RELAY BEING CONNECTED FROM A THIRD POINT BETWEEN THE BATTERY AND THE STARTER SWITCH ON THE ONE HAND AND GROUND ON THE OTHER HAND. 